Method and system for propagating data between different domains in a privacy focused way

ABSTRACT

A method for recording information within first-party cookies on a web browser, including propagating recorded information from a second cookie associated with a second domain to a first cookie associated with a first domain, wherein the first cookie and the second cookie are each first-party cookies, such that a first web resource of the first domain and a second web resource of the second domain each have access to the recorded information via its associated first-party cookie, and corresponding server and system.

FIELD OF THE INVENTION

The invention generally relates to methods for utilising first-party cookies in place of third-party cookies.

BACKGROUND TO THE INVENTION

Web browsing has developed from simple hyper-text linking between static web pages to a dynamic interconnection of many static and dynamically generated websites providing extensive content.

As browsing developed, a need to be able to record information associated with websites was addressed by enabling websites to set “cookies”—small pieces of data stored on a computer running a web browser in response to an instruction made by a website being accessed by the web browser.

A cookie can be a “first-party cookie” or a “third-party cookie”. The former are set by the particular domain being accessed by the web browser. For example, a user may direct the web browser to www.example.com, and the web content accessed at this domain by the web browser may instruct recording of a cookie containing data and associated with the same domain (hence the term “first-party”). The latter are set by a different domain to that being accessed by the web browser. For example, the web page being accessed at www.example.com may itself utilise resources of another domain, for example, www.addomain.com. This resource may itself set a cookie—however, as it is associated with a different domain, the cookie is associated with the second domain. Hence, the cookie is a third-party cookie; it is associated with a different party to that of the domain being accessed by the web browser.

There has been a trend of preferring to not allow setting of third-party cookies—for example, as a user is not necessarily aware of the second domain, setting of a third-party cookie may be considered undesirable. However, third-party cookies play an important role in modern online activities, providing means to track activity among different websites (for example, for providing targeted advertising) and to allow for more efficient user identification. For example, a common owner of several websites (each associated with a different domain) may have legitimate interests in identifying a user when that user visits its unique websites; the removal of third-party cookies, although for the positive reason of improving user privacy and security, is likely to have negative consequences in these circumstances.

As an example, when user (via a web browser) accesses a known domain, such as www.example.com, it may generate at least some of the content for the user by utilising resources from a third-party domain, for example www.addomain.com. In the past, www.addomain.com may set a third-party cookie (for example, with name=AdDomainld and value=12345). In terms of a browser functionality, this cookie is related to www.addomain.com rather than www.example.com. When a user further navigates to www.example01.com, a domain totally unrelated to www.example.com and owned by another company, that which also utilises resources of www.addomain.com, in the past the browser would automatically send the cookie for www.addomain.com to www.addomain.com. This means that a cookie that was previously set on www.example.com (name=AdDomainld with value=12345) is automatically sent from www.example01.com.

Therefore, recently, several major web browser developers have announced plans to disable third-party cookies by default. Such an action is predicted to have an adverse consequence on legitimate online activity.

It would be desirable to provide a mechanism for enabling functionality provided by third-party cookies without requiring setting of third-party cookies.

SUMMARY OF THE INVENTION

Embodiments and aspects described herein are generally directed towards providing mechanisms for enabling functionality provided by third-party cookies without requiring the setting of third-party cookies. For example, certain described embodiments may be suitable for providing functionality to enable tracking of particular users amongst several different websites associated with different domains, which may advantageously enable identification of a user by said different websites in a manner invisible to said user. Advantageously, identification of a user may allow the different websites to offer suitably tailored content based on the user identification, thereby providing an improved user experience across the various websites and domains. These and other advantages are generally achieved without setting third party cookies, which previously have been utilised to provide such function. In order to strike a balance between legitimate tracking activities and the desire for user privacy and security, certain described embodiments provide for additional limitations on the extent to which user identifying information is made available.

According to an aspect of the present invention, there is provided a method for recording information within first-party cookies on a web browser, for example wherein the web browser does not allow access to third-party cookies, including propagating recorded information from a second cookie associated with a second domain to a first cookie associated with a first domain, wherein the first cookie and the second cookie are each first-party cookies, such that a first web resource of the first domain and a second web resource of the second domain each have access to the recorded information via its associated first-party cookie.

The recorded information may be propagated to the first cookie during a current communication instance between the web browser and the first web resource of the first domain. The recorded information may be propagated to the first cookie in dependence on a determination of the absence of the first cookie.

The recorded information may be propagated via an intermediary, the intermediary being propagation information accessible to the web browser during the current communication instance.

According to an embodiment, the method comprises instructing the web browser, during the current communication instance, to communicate to a propagation server associated with a propagation domain different to the first domain, and receiving from the propagation server the propagation information such that the web browser is enabled to record as a first cookie the recorded information. The web browser may initiate the current communication instance via a communication to a first web server requesting content for display, the first web server associated with a first domain server and both said servers may be associated with the first domain, and the instruction to the propagation server may be received from the first domain server. The first web server may provide the content for display to the web browser in dependence on the recorded information after propagation of the recorded information from the second cookie to the first cookie. As part of the instruction, the web browser may provide information stored in a propagation cookie to the propagation server, and the propagation information may be based on the information stored in a propagation cookie. The information stored in a propagation cookie and the propagation information may be the same or the propagation information may be an encoded representation of the information stored in a propagation cookie. The propagation information may be generated according to propagation rules available to the propagation server, the propagation rules may be applied to the information stored in a propagation cookie. The propagation rules may be stored within the propagation cookie and provided to the propagation server as part of the instruction. The propagation information may be provided to the web browser in association with an instruction received from the propagation server, such that the web browser may be caused to communicate with the first domain server and provide the propagation information with the instruction. The web browser may receive an instruction from the first domain server, in response to providing the propagation information to the first domain server, to set the first cookie comprising the recorded information.

According to an embodiment, the intermediary is stored as web page specific data, and comprising: instructing the web browser to communicate with a first domain server, the web browser providing the web page specific data to the first domain server with the instruction; and receiving from the first domain server an instruction to set the first cookie with the recorded information, wherein the recorded information is equal to or derived from the web page specific data, wherein the instruction is received from a first web server in response to a request for content for display made by the web browser, wherein the first web server is associated with the first domain server, and wherein both said servers are associated with the first domain. The web page specific data may be set during a previous communication instance with the second domain server of the second domain. The web page specific data may not be accessible to executable code when run on the web browser and may be accessible to a first domain server when set by a communication with the second domain, and preferably is only accessible by an external server. The web page specific data may be stored in an ETag associated with a web page provided to the web browser before the instruction is sent to the web browser.

The first domain and second domain may be determined to be related domains for which propagation is allowed before allowing propagation for the recorded information from the second cookie to the first cookie.

The web browser may not allow access to third-party cookies.

According to another aspect of the present invention, there is provided a domain server configured for communication with web browsers for facilitating propagation of recorded information between first-party cookies associated with different domains, the domain server configured to: receive a communication from a web browser due to a redirection instruction provided to the web browser from a first web server associated with the first domain; and determine whether a first cookie is present with the communication, the first cookie associated with the first domain, and wherein, in response to determining that there is not a first cookie present, the domain server is configured to: obtain from the web browser propagation information, the propagation information derived from recorded information of a second cookie associated with a second domain, wherein the recorded information is derivable from the propagation information; determine the recorded information from the propagation information; and instruct the web browser to record in a first cookie the recorded information.

The domain server may be configured to instruct the web browser to communicate with the first web server to enable generation of content for the web browser utilising the recoded first cookie.

In an embodiment, the domain server is further configured to, when obtaining the intermediary information: instruct the web browser to communicate with a propagation server associated with a propagation domain different to the first domain, wherein the propagation information is provided to the web browser from the propagation server in response to the instruction; and receive the propagation information from the web browser after the web browser is instructed to communicate again with the domain server. The propagation information may be generated according to propagation rules available to the propagation server, and the propagation rules may be applied to the information stored in a propagation cookie. The propagation rules may be stored within a propagation cookie stored in the web browser.

In an embodiment, the intermediary is stored as web page specific data, and wherein the domain server is further configured to: identify the web page specific data from the communication from the web browser; and communicate an instruction to set the first cookie with the recorded information, wherein the recorded information is equal to or derived from the web page specific data. The web page specific data may be set during a previous communication instance with a second domain server of a second domain. The web page specific data may not be accessible to executable code when run on the web browser and may be accessible to the first domain server when set by a communication with the second domain, and preferably is only accessible by an external server. The web page specific data may be stored in an ETag associated with a web page provided to the web browser before the instruction is communicated. The recorded information may be only propagated from the second cookie to the first cookie when the second domain is identified as being related to the first domain.

The web browser in communication with the domain server may not allow access to third-party cookies.

According to yet another aspect of the present invention, there is provided a network system for facilitating propagation of recorded information between first-party cookies associated with different domains on a web browser in communication with the network system, the system comprising: one or more domain servers, wherein each domain server is configured to: receive a communication from a web browser due to a redirection instruction provided to the web browser from a web server associated with the domain; determine whether a first cookie is present with the communication, the first cookie associated with the domain; in response to determining that there is not a first cookie present, obtain from the web browser propagation information, the propagation information derived from recorded information of a second cookie associated with second domain, the second domain associated with another of the domain servers, wherein the recorded information is derivable from the propagation information; determine the recorded information from the propagation information; and instruct the web browser to record in a first cookie the recorded information.

Optionally, the network system comprises a propagation server associated with a propagation domain different to the first domain, and wherein each domain server is further configured to, when obtaining the intermediary information: instruct the web browser to communicate with the propagation server associated with a propagation domain different to the first domain; and receive the propagation information from the web browser after the web browser is instructed to communicate again with the domain server by the propagation server, and wherein the propagation server is configured to: determine the propagation information based on information provided from the web browser with the instruction. The information may comprise, if present, that stored in a propagation cookie readable by the propagation server. The propagation server may be configured to generate the propagation information according to propagation rules available to the propagation server, and the propagation rules may be applied to the information stored in a propagation cookie. The propagation rules may be stored within a propagation cookie stored in the web browser and may therefore be received by the propagation server via the communication from the web browser. In a case where a propagation cookie is not present, the propagation server may be configured to determine a value for a propagation cookie and to communicate an instruction to the web browser to set the value as a propagation cookie, and the propagation information may be generated in accordance with the newly determined value.

Optionally, each domain server is further configured to: identify web page specific data from the communication from the web browser; and communicate an instruction to set the first cookie with the recorded information to the web browser, wherein the recorded information is equal to or derived from the web page specific data. The web page specific data may be set during a previous communication instance with the second domain server.

The recorded information may be only propagated from the second cookie to the first cookie when the second domain is identified as being related to the first domain.

The network system may further comprise a web server for each domain server, the web server may be configured to instruct a web browser to communicate with its associated domain server, and each web server may share a domain with its associated domain server.

A web browser in communication with the system may be assumed to or may not allow access to third-party cookies.

As used herein, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood, embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a communication system according to an embodiment;

FIG. 2 shows an arrangement for cookie propagation for certain embodiments;

FIG. 3 shows a method for propagating cookies, according to an embodiment;

FIGS. 4A and 4B shows a particular implementation utilising the method of FIG. 3;

FIGS. 5A and 5B show a method for propagating cookies, according to another embodiment;

FIG. 6 shows a method for generating a domain cookie via a third-party content server;

FIGS. 7A-7C show embodiments for generating a user identifying cookie and propagating the information; and

FIGS. 8A-8E relate to using a proxy server to modify communications to a third-party resource.

DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a communication system 10 according to an embodiment. The system 10 comprises a client device 11, a web server 12, a domain server 13, and an optional (third-party) content server 14. The client device 11 is configured for data communication with the web server 12, domain server 13, and, when applicable, content server 14 via a network 15, typically comprising the Internet. In the embodiment shown, the client device 11 is in data communication with the content server 14 via the domain server 13.

The system 10 of FIG. 1 should be understood as an exemplary representation of data connections between various elements, however, should not be considered limiting; for example, certain embodiments may utilise fewer elements than shown while others may utilise additional elements. Furthermore, the various servers 12-14 should be understood, unless otherwise stated, as representing functional elements—although each server 12-14 may be embodied in separate physical hardware, two or more of said servers 12-14 may be embodied in the same physical hardware, for example as logically distinct elements. Similarly, the client device 11 should be understood, unless otherwise stated, as a functional element allowing a user (or, in fact, users) to interact with the system 11.

The client device 11 is configured to run an application suitable for requesting web content (e.g. via the http protocol), typically a web browser (as assumed herein). The web browser is enabled to communicate with the web server 12 hosting a particular website. For example, the web browser can make such a communication in response to a user input (e.g. by selecting a hyperlink directed towards the website or by entering an URL address of the website) or automatically in response to an instruction made by software executed on the client device 11 (which can be the same web browser).

A client device 11 can be any suitable computing hardware for running the application suitable for requesting web content, such as a personal computer (PC) or smartphone. Other devices are also envisaged, such as smart watches, tablets, and various formfactor of PC including desktop, laptop, and netbook. A common property of said client devices 11 is enablement of network data communication with the network 15, such as wired (e.g. via Ethernet) or wireless (e.g. WiFi—such as one or more of the various IEEE 802.11 standards). For the purposes of the present disclosure, no particular data communication is assumed. The client device 11 can implement any number of operating systems, such as one or more of Microsoft Windows-compatible operating system (OS), Apple OS X, and a Linux distribution.

Smartphones are known to implement Android or iOS operating systems, amongst others.

The various servers 12-14 can be implemented in appropriate hardware as desired. For example, each server 12-14 can be implemented in dedicated computing hardware. However, cloud-based implementations are also envisaged, such as provided by Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform, and Oracle Cloud, in which one or more servers 12-14 are implemented as virtual servers. Generally, each server 12-14 is associated with a processor and memory, wherein the processor executes code to implement the functionality of said server 12-14 and the memory is provided to store said code as well as to provide a working memory space. The memory can comprise both volatile and non-volatile memories. Each server 12-14 is provided with access to said network 15 and/or directly to one or more of the other servers 12-14, depending on the requirements of the particular implementation.

Generally, the network 15 is flexible and may receive data communications via any number of protocols, such as Ethernet, 802.11, worldwide interoperability for microwave access (WiMAX), 3G, 4G, CDMA, digital subscriber line (DSL), etc. Similarly, the networking protocols used on the network 15 can include any number of protocols, such as multiprotocol label switching (MPLS), the transmission control protocol/Internet protocol (TCP/IP), the User Datagram Protocol (UDP), the hypertext transport protocol (HTTP), the simple mail transfer protocol (SMTP), and the file transfer protocol (FTP). The data exchanged over the network 15 can be represented using technologies and/or formats, for example, one or more of: the hypertext mark-up language (HTML), the extensible mark-up language (XML), and JavaScript Object Notation (JSON). In addition, all or some of communications can be encrypted using conventional encryption technologies such as secure sockets layer (SSL), transport layer security (TLS), and Internet Protocol security (IPsec).

Reference herein is made to “browser executable code”, with a primary example being JavaScript. JavaScript is a well-known technology of the world Wide Web, itself an application running on the Internet. Although, by some estimates, 97% of websites use JavaScript for client-side web page behaviour (that is, generating web page content and behaviours through execution of JavaScript of the web browser of client devices 11), the particular browser executable code and corresponding programming language should not be considered constraining, unless the context or particular claims dictates otherwise. Relevantly, the browser executable code should be suitable for execution on a web browser of a client device 11 to cause the web browser to undertake communication functions, generate content, or other dynamic behaviours.

Various embodiments are described below for providing functionality without utilising third-party cookies which may be similar in effect (at least, from the perspective of the user of the user device 11) to certain functionality known to be enabled by the setting of third party cookies. Generally, the scenarios described herein include a web browser accessing an internet resource being a web page (as assumed herein) hosted by the web server 12. The web browser is directed to the address of the web page specified, for example, by its Uniform Resource Locator (URL).

According to embodiments, both the web server 12 and the domain server 13 are configured to receive requests from the client device 11 and to provide a response. For example, a request can be for content and the response can comprise that content. Typically, as assumed herein, the requests are according to the Hypertext Transfer Protocol (HTTP) (or an extension protocol such as Hypertext Transfer Protocol Secure (HTTPS)) “GET” messages and the responses comprise HTTP/HTTPS response messages. Additionally, a response can comprise content including hypertext mark-up language (HTML) code defining an appearance and functionality of the web page. The HTML code define a variety of different pieces of content. The response also comprises HTTP headers.

Generally, when a web browser of user device 11 accesses an internet resource, it can be configured to communicate web page specific data with the request that has previously been stored by the web browser due to a previous access of the internet resource. An example is an ETag (having an ETag value). An ETag is defined as a part of HTTP and is set on the client device 11 by the resource when responding to the request. That is, if the web browser has previously communicated with the resource, it can have stored an ETag value that was set during the previous communication. Generally, the ETag value is specifically associated with the resource, for example, associated with its URL. ETag values can be valid for a time limit or not. In another embodiment, the web page specific data is stored in a local storage accessible to the web browser, for example, via execution of suitable code. For convenience, certain embodiments are described herein which relate to the use of ETags as the web page specific data, although it should be understood this is not intended to be limiting.

The web browser operating on the client device 11 is configured to store data in the form of cookies. The cookies can be of a variety of types known in the art. Relevantly, the web page specific data is not equivalent to a cookie—for example, for the purposes of the present disclosure, the web page specific data is unavailable to executable code.

Referring to FIG. 2, a topology is shown relevant for certain embodiments in which a plurality of web servers 12 a-12 c (generally, any number of web servers 12) are in communication with network 15. Domain server 13 is also shown in communication with the network 15. As with FIG. 1, a representative client device 11 is also shown in communication with the network 15; therefore, client device 11 is enabled to communicate with each web server 12 a-12 c and the domain server 13 via said network 15.

Relevantly, the web servers 12 a-12 c are distinguished in that they represent web resources (e.g. web pages) associated with different domains (represented by broken-lined boxes); that is, first web server 12 a is associated with a first web page on a first domain (e.g. www.example1.com), second web server 12 b is associated with a second web page on a second domain (e.g. www.example2.com), and third web server 12 a is associated with a third web page on a third domain (e.g. www.example3.com). Therefore, first party cookies associated with each web server 12 a-12 c are not accessible to the other web servers 12 a-12 c.

One or more embodiments herein described can be utilised to “propagate” cookies between the different domains. Here, “propagate” and “cookie propagation” refer to creating first party cookies on the client device 11 associated with each domain based on common information. For example, if information is created or determined by a visit by the client device 11 to a web resource of one of the domains (e.g. the first domain) and recorded within a first-party cookie, a subsequent visit to a web resource of another of the domains (e.g. the second domain) results in the recording of the information within a first-party cookie associated with this next visited domain. Therefore, the common information is effectively stored in separate first party cookies for each web resource of the different domains.

The overall effect is that the common information is “propagated” between cookies for each domain, thereby enabling each web server 12 a-12 c to generate consistently personalised information by being enabled to identify each visit as being from the same client device 11. In practice, any required information can be propagated. It should also be understood that each domain's cookie can store different actual data (e.g. via domain specific encryption and/or hashing)—however, the common information should be derivable from each domain's cookie.

Certain embodiments utilise “related” web servers 12 a-12 c, by which there is a common relationship between each individual web server 12 a-12 c. For example, each related web server 12 a-12 c may be “owned” (that is, at least operated) by a common entity but providing different services on the different domains. In one illustrative example, the first domain references a car sale service (e.g. advertising and facilitating sales of cars between individuals and/or companies), the second domain references a non-vehicle property sale service (e.g. an auction service), and the third domain references a content provision service (e.g. a news website). Each of these services is offered by a common entity (e.g. Company A) but under different branding and/or owned companies, and therefore, each service is associated with a unique domain.

In the prior art, third-party cookies are utilised to store common information (e.g. an identifier unique to the particular client device 11, and which may also be unique to the particular web browser and/or user of the web browser) that is then accessed by each web server 12 a-12 c to enable each service to offer individualised content to the user associated with that identifier, as the third-party cookie is accessible by each separate domain.

One or more embodiments described herein are therefore directed towards providing similar functionality of making accessible the common information but with avoiding the use of third-party cookies. Depending on the embodiment and implementation, the manner in which said information is utilised may be left to the particular web servers 12 a-12 c.

For the purposes of the present disclosure, a cookie set in relation to a particular domain is referred to as a “domain cookie”. Labels such as “first” and “second” are utilised to distinguish between different domains and their associated web servers 12 and domain servers 13. Similarly, common lowercase suffixes are used to identify different features of the figures that are related to a particular domain. For example, a first web server 12 a and a first domain server 13 a are addressable at a first domain which can be associated with a first domain cookie, a second web server 12 b and a second domain server 13 b are addressable at a second domain which can be associated with a second domain cookie, and a third web server 12 c and a third domain server 13 c are addressable at a third domain, which can be associated with a third domain cookie.

According to an embodiment, with reference to FIGS. 3A and 3B, a method is described relating to setting non-cookie web page specific data within the web browser of a client device 11. One example known in the art is an ETag. The method also describes setting a first domain cookie on the web browser of the client device 11 in relation to a first web page. The first domain cookie is a first-party cookie, in that it is set in association with the same domain as the first web page (first domain), although it is set by the first domain server 13 a rather than the first web server 12 a. Relevantly, the first domain cookie is accessible by executable code— for example, the first domain cookie does not have the “HttpOnly” attribute set. Relevantly, the web page specific data should be of a form which is not accessible to the code executed on the client device 11—for example, an ETag value is not accessible by JavaScript. It can be preferred that the web page specific data is only accessible to web-based servers such as the web servers 12 and domain servers 13.

At step 300, the client device 11 communicates a request for content to the first web server 12 a, which as described above is associated with a first domain (e.g. www.example1.com). The request typically will specify a particular web page for which content is desired—it should be noted that a default web page can be selected (e.g. http://www.example1.com/index.html). At step 301, a response is communicated to the client device 11 from the first web server 12 a, the response being determined in accordance with the request. The response comprises a domain server communication instruction (as executable code) for execution by the web browser of the client device 11 (e.g. in the form of JavaScript code) as well as, typically, content for display on the web browser.

The domain server communication instruction is an instruction for the web browser of the client device 11 to communicate with the first domain server 13 a. Relevantly, the domain server 13 is present on the same domain as the first web server 12 a, although the domain server 13 can be located at a different IP address to the web server 12. In a particular implementation, a subdomain of the first domain is used to address the first domain server 13 a (e.g. http://processing.example1.com). Therefore, as discussed above, a first domain cookie set due to communication with the first domain server 13 a will be a first-party cookie (due to sharing its domain with the first web server 12 a).

Depending on the embodiment, the domain server communication instruction comprises a first executable code configured to cause the web browser to communicate with the first domain server 13 a. Alternatively, the domain server communication instruction comprises an instruction for the web browser to obtain the first executable code from the domain server 13 a. In either case, as a result of step 301, the web browser is provided with the first executable code.

At step 302, the web browser executes the first code. The first code is configured to undertake a check step 303. Here, the web browser performs a check for a first domain cookie previously stored by the web browser. As previously discussed, the first domain cookie, if present, is accessible to the first code. Relevantly, as discussed, the first domain cookie is associated with the domain of the web page (i.e. the first domain).

If the first domain cookie is not present, then the first code is configured to cause the web browser to communicate a request to the first domain server 13 a, at step 310. If available, an ETag value (or, depending on the embodiment, other web page specific data) associated with the web page is communicated with the request (for ETags, if present, the ETag value will be communicated as defined by the HTTP standard).

Next, at step 311, the first domain server 13 a is configured, upon receiving the request, to determine whether the ETag value is present with the request.

The presence of the ETag value in this situation (where a first domain cookie is not present) indicates to the first domain server 13 a that the web browser has previously accessed a second website (e.g. associated with the second web server 12 b), hosted on a different domain (e.g. the second domain) to the first website, and had a second domain cookie set in relation to the second domain by the second domain server 13 b (therefore, the second domain cookie is a first-party cookie of the second domain, and therefore not accessible in communications with the first domain server 13 a). In this scenario, the first domain server 13 a is configured to communicate a reply to the client device 11 setting a domain cookie associated with the first domain with a value derived from (for example, comprising) the ETag value, at step 314. As a result, the web browser stores a “first-party” first domain cookie associated with the first domain which records the same information as the second domain cookie associated with the second domain.

If an ETag value is not present, then the first domain server 13 a is configured to determine data for storing in both a first domain cookie and as an ETag value, at step 312, and to send a response to the web browser of the client device 11 instructing it to set both the first domain cookie and the ETag value, at step 313. Regarding step 312, the particular means by which the first domain server 13 a determines the data depends on the implementation. However, in one particular example, the data is obtained or derived from the content server 14 (for example, from a set-cookie command issued by the content server 14)—in this case, the first domain cookie and ETag value reflect the information intended for storage obtained from the content server 14. The set-cookie command issued by the content server 14 is effectively an instruction to set a third-party cookie, as the content server 14 is on a different domain to the first domain. In another example, the first domain server 13 a is itself configured to determine the data for storing as the first domain cookie and ETag value—it can be, for example, a randomly or procedurally generated identifier or other data for future use by the web servers 12 a-12 c and/or the domain servers 13 a-13 c.

Considering now a result of check step 303 where the first domain cookie is present. The first code is configured to, in response, cause the web browser to communicate a request to the first domain server 13 a, at step 320. The request is accompanied by the information stored within the first domain cookie (thereby making the information available to the first domain server 13 a) and, where available, an ETag value (or, depending on the embodiment, other web page specific data).

At step 321, the first domain server 13 a checks whether the request is accompanied by the ETag value.

If the request is not accompanied by an ETag value, then the first domain server 13 a communicates a response to the client device 11 comprising a set ETag instruction, where the ETag is set to the value of the first domain cookie (or at least, a value derived from the first domain cookie data), at step 322. In this way, in effect, the web browser has stored the information recorded within the first domain cookie value in the ETag.

On the other hand, if the request is accompanied by an ETag value, then the first domain server 13 a can communicate a response to the client device 11 specifying that no update is required to either the ETag or the domain cookie, at step 323. Equivalently, the response can be an instruction to refresh either or both of the ETag value and the first domain cookie (for example, this may be useful where either or both of the ETag and domain cookie have a finite lifetime).

FIG. 3 therefore defines a mechanism by which the data of a first-party domain cookie associated with a one web page can be copied to a first-party domain cookie associated with another web page. Therefore, the data need only be determined once, in relation to the one web page, and then propagated amongst any other web pages associated with other domains. As a result, the method of FIG. 3 provides first-party domain cookies for each different domain recording the same information—in effect therefore, the collection of first-party domain cookies can advantageously provide a similar function as a single third-party cookie.

According to an embodiment, one or more of the related domain cookies are modified with respect to the original information. For example, a domain cookie can be subjected to an anonymisation routine in order to obfuscate the original information. It is preferred that the modification is reversible by the relevant domain server 13—such that, a domain server 13 is accurately enabled to determine the original information from its associated domain cookie. For example, encryption keys can be utilised using, for example, the domain names of the domain cookies such that each domain cookie is associated with different encryption output derived from the same information. In another example, a random prefix and/or suffix of known size (known, that is, to the related domain server 13) is attached.

FIGS. 4A and 4B show an example implementation of the embodiment of FIG. 3. At step 400, a user of a web browser on the client device 11 directs the web browser to a first web page hosted by first web server 12 a. The first web server 12 a returns a response comprising the html code defining the content for display on the client device 11, at step 401. The response also comprises first executable code comprising instructions as discussed with reference to FIG. 3, at step 402. Alternatively, the response comprises an instruction to obtain said first executable code from the first domain server 13 a, and the web browser obtains the first executable code as a result (again, at step 402).

At step 403, the web browser, due to execution of the first executable code, communicates with the first domain server 13 a and communicates, if available, a first domain cookie associated with the first domain server 13 a. The first domain server 13 a also obtains an ETag value (or more generally, web page specific data which is not accessible to the executable code and is accessible to the first domain server 13 a irrespective of which domain server 13 originally set the web page specific data value (i.e. which domain was accessed when the web page specific data was set). For example, the web browser of the client device 11 access a web resource, such as an image, located on the first domain server 13 a and, in doing so, communicates an ETag value (if available) to the first domain server 13 a associated with the image. The first domain server 13 a is therefore configured to identify the ETag value of the particular image. The first domain cookie will be available if previously set by the first domain server 13 a due to a previous communication. The ETag will be available if previously set by any one of the domain servers 13 due to a previous communication (e.g. when the image is communicated to the client device 11, an appropriate ETag value (according to embodiments herein described) is set in association with the image.

FIG. 4A shows a situation where neither the first domain cookie nor the ETag are available for communication to the first domain server 13 a, determined at step 404. In this case, the method of FIG. 3 results in step 313 (setting a value for the first domain cookie and the ETag). The value for the ETag and the first domain cookie can be generated by the first domain server 13 a, the first web server 12 a, or a content server 14 (depending on the implementation).

According to this particular example, the first domain cookie (first domain) is set in a first communication, at step 405. The web browser is then configured to communicate again with the first domain server 13 a, sending at step 406 a data of the first domain cookie (which is now set due to step 505). Considering the method of FIG. 3, the first domain server 13 a will end at step 322—a response is communicated at step 407 to the client device 11 instructing it to set an ETag equivalent to the first domain cookie (first domain). In this sense, the first executable code is essentially run twice—the first execution giving the result of step 313 of FIG. 3 and the second execution giving the result of step 322 of FIG. 3.

FIG. 4B shows a situation where the first domain cookie (first domain) is not available but the ETag is available for communication to the first domain server 13 a, determined at step 404. In this case, the method of FIG. 3 results in step 314 (setting a value for the first domain cookie based on the ETag). The implication is that the web browser has visited a web page hosted on a different domain to the current web page, but that utilises a related domain server 13. Therefore, another domain cookie has been set in relation to the different domain and can be utilised for setting a first domain cookie for the first domain.

According to this example, first domain cookie (first domain) is set by a response communicated from the first domain server 13 a to the client device 11, at step 408. Further execution of the method of FIG. 3 can occur during the current process but will result in step 323 of FIG. 3—no action required. Again, in this sense, the first executable code can be run twice—the first execution giving the result of step 314 of FIG. 3 and the second execution giving the result of step 323 of FIG. 3.

The embodiment of FIG. 3 (and examples of FIGS. 4A and 4B) therefore utilises non-cookie web page specific data stored on the web browser of a client device 11 to effectively “signal” whether another domain cookie for another related domain is present, when a web page of a first domain is accessed.

According to an embodiment, a propagation server 16 is associated with a propagator domain (e.g. www.exampleserver.com), as shown in FIG. 5A. The propagation server 16 is configured to facilitate propagation of cookie information among domain cookies, which are each associated with one of a plurality of domain servers 13 a-13 c—that is, the propagation server 16 can facilitate an exchange data with each domain server 13 a-13 c. The propagation server 16 is in data communication with the network 15. It is possible that one or more of the domain servers 13 can be embodied as a logical function of the propagation server 16, although it may be preferred that each domain server 13 is logically and/or physically distinct to the propagation server 16. Also shown in FIG. 5A is a plurality of web servers 12 a-12 c. As with FIG. 1, a representative client device 11 is also shown in communication with the network 15; therefore, client device 11 is enabled to communicate with each web server 12 a-12 c, each domain server 13 a-13 c, and the propagation server 16, via said network 15. Relevantly, each domain server 13 a-13 c is addressable at a respective domain as one of the web servers 12 a-12 c as described above.

In an implementation, each domain server 13 is addressable via a subdomain of its associated domain. The subdomains can be labelled as desired, it is relevant that each is resolvable to the network address (e.g. IP address and optionally TCP or UDP port number) of the associated domain server 13. Each domain server 13 can be located at the same or different IP address to its associated web server 12, depending on the implementation.

FIG. 5B shows a method relating to setting a first domain cookie associated with the first domain and therefore accessible to the first web server 12 a and the first domain server 13 a, in dependence on the presence and value of a common cookie (“propagator cookie”) associated with the propagator domain. The common cookie can be, for example, an identifier associated with the particular client device 11 (in this case, referred to herein as a “userID”).

At step 500, the client device 11 communicates a request for content to first web server 12 a. The request typically will specify a particular web page for which content is desired—it should be noted that a default web page can be selected (e.g. http://www.example1.com/index.html). At step 501, a response is communicated to the client device 11 from the first web server 12 a, the response being determined in accordance with the request. The response comprises a domain server communication instruction (as executable code) for execution by the web browser of the client device 11 (e.g. in the form of JavaScript code), configured to cause the client device 11 to communicate to the first domain server 13 a. The response also, typically, comprises content for display on the web browser. Alternatively, or in addition, the first web server 12 a can send a redirect instruction (e.g. via Location headers in the response) to the first domain server 13 a.

At step 503, the first domain server 13 a receives the communication from the client device 11 and analyses the content to determine if a previously set first domain cookie is present (typically in headers in the case of HTTP).

In a case where a first domain cookie is present (e.g. cookie propagation is not required), the method simply proceeds to web-page rendering step 512 (discussed below), which can be effected by the first domain server 13 a communicating an instruction to the client device 11 to undertake a further communication to the first web server 12 a.

In a case where a first domain cookie is not present (e.g. cookie propagation or initial creation is required), the first domain server 13 a communicates a response to the client device 11 from the first web server 12 a, at step 504. The response comprises a propagation server communication instruction (e.g. as executable code) for execution by the web browser of the client device 11 (e.g. in the form of JavaScript code), configured to cause the client device 11 to communicate to the propagation server 16. Alternatively, or in addition, the first domain server 13 a can send a redirect instruction (e.g. via Location headers in the response) to the propagation server 16. In response, the client device 11 communicates a request to the propagation server 16 at step 505, the request optionally including information identifying the first domain server 13 a (for example, information can be passed in a URL or via a suitable network protocol).

At step 506, the propagation server 16 receives the communication from the client device 11 and analyses the content to determine if a propagator cookie is present (typically in headers in the case of HTTP), at step 505. The presence of a propagator cookie indicates that the client device 11 has previously visited a related domain (e.g. the second or third domain) resulting in a domain cookie (e.g. second domain cookie or third domain cookie) being set in relation to the related domain. The absence of a propagator cookie indicates that the client device 11 has not previously visited a related domain and had a domain cookie set for the related domain.

In a case where a propagator cookie is not present, at step 507, the propagation server 16 is configured to determine information for recording within a new propagator cookie on the client device 11. The information can be randomly generated or procedurally generated, or alternatively, generated via a communication with a content server 14 (not shown in FIG. 5B).

In either case, the propagation server 16 communicates a response to the client device 11, at step 508. The response comprises a domain server communication instruction (e.g. as executable code) for execution by the web browser of the client device 11 (e.g. in the form of JavaScript code), configured to cause the client device 11 to communicate to the original domain server 13 (i.e. in this example, the first domain server 13 a), at step 509. Alternatively, or in addition, the propagation server 16 can directly effect a redirect (e.g. via Location headers in the response) to the first domain server 163.

In the case that step 507 is performed, the response also comprises a set propagator cookie command to cause the client device 11 to set a propagator associated with the propagator domain recording the generated information.

In response, the client device 11 then communicates a request to the first domain server 13 a, at step 510. In response to the request, at step 511, the first domain server 13 a is configured to determine the information recorded in the propagator cookie and communicates a response to the client device 11 comprising a set cookie command to cause the client device 11 to set a first domain cookie associated with the first domain recording the information.

In an embodiment, the domain server 13 a obtains the information from the web browser of the client device 11. For example, the domain server communication instruction of step 508 includes the information recorded in the propagator cookie and is configured to cause the web browser of the client device 11 to communicate the information (which is preferably encrypted) to the first domain server 13 a. For example, the information can be passed in a URL or via a suitable network protocol. Here, the client device 11 is effectively utilised as an intermediary, which may advantageously allow for method to avoid direct communications between the propagation server 16 and the domain servers 13—this may provide for improved privacy and/or security (or at least a perception of an improvement).

In an alternative embodiment, the propagation server 16 is configured to identify the first domain server 13 a (more generally, the particular domain server 13 which initiated the client device 11 communication to the propagation server 16, derivable from the request received by the propagation server 16) and to communicate the generated or previously recorded information for the propagator cookie (or, at least, data derived from the recorded information) to the first domain server 13 a along with, typically, information identifying the particular client device 11.

The response also comprises a web server communication instruction (e.g. as executable code) for execution by the web browser of the client device 11 (e.g. in the form of JavaScript code), configured to cause the client device 11 to communicate to the original web server 12 (i.e. in this example, the first web server 12 a). Alternatively, or in addition, the first domain server 13 a can send a redirect instruction (e.g. via Location headers in the response) to the first web server 12 a.

The method then proceeds to web page rendering step 512 (which can also be arrived at after step 503). At this step, the first web server 12 a communicates with the client device 11 (which may comprise multiple separate instances of communication) and can utilise the content of the first domain cookie to generated personalised content—the first domain cookie is accessible to the first web server 12 a due to it sharing the first domain with the first domain server 13 a.

Accordingly, the method of FIG. 5B can be utilised to effectively propagate cookies (or more generally, the information recorded in a cookie can be propagated amongst different domain cookies) across the various web servers 12 a-12 c. The propagator cookie is utilised to signal to the propagation server 16 whether or not (through its presence or absence) a client device accessing a particular web server 12 has previously visited another related web server 12 on another domain and, therefore, previously generated information intended to be commonly available to the plurality of related web servers 12 (e.g. all web servers 12 a-12 c). For example, the information can be a UserID suitable for identifying that the particular client device 11 (or a particular user of said client device 11) has previously visited related websites on different domains. In the case of the information recoded in the propagator cookie being an identifier such as a UserID, the domain cookies can record the UserID or information derived from the UserID as DomainIDs (that is, each DomainID is for the particular domain, but are related in a manner that enables identification of the user). Therefore, the collection of domain cookies having related DomainIDs can be utilised by the related web servers 12 to generate personalised information for the client device 11. The direct communication between the domain servers 1 and the propagation server 16 enables the effective propagation.

According to an embodiment, with reference to FIGS. 7A-7C, the propagation server 16 is interfaced with a rules module 18 (see FIG. 7A). The rules module 18 can be a logical function of the propagation server 16 (assumed herein) or can be implemented as a different physical or logical server in data communication with the propagation server 16. Also shown are four web servers 12 a-12 d, where web servers 12 a, 12 b are associated with a first group 20 a and web servers 12 c and 12 d are associated with a second group 20 b. Although web servers 12 can be grouped according to any particular relationship, for the present purposes, it is assumed that the first group 20 a comprises web servers 12 a, 12 b of domains administered (e.g. owned) by a first entity and that second first group 20 b comprises web servers 12 c, 12 d of domains administered (e.g. owned) by a second entity, different to the first. Relevantly, according to the present embodiment, propagation server 16 is configured to manage cookie propagation for all web servers 12 a-12 d (more generally, web servers 12 belonging to different groups 20).

The rules module 18 is configured to apply propagation rules before communication of a response comprising a domain cookie to a client device 11 and/or domain server 13 (depending on the embodiment). The propagation rule are used to determine the whether a domain cookie is set and, if so, with what specific data (for example, the specific data can record common information to other domain cookies and/or the propagation cookie in a different format, for example, due to unique encryption which may be associated with the particular domain).

In an embodiment, the propagation rule for use in generating data for a particular domain cookie is stored in the associated propagation cookie itself; therefore, the propagation rules in this embodiment are stored in the user's web browser which may advantageously avoid a central location of propagation rules of a number of different users. In this embodiment, the propagation rules are usually recorded in an encrypted form such that a direct read of the propagation cookie does not reveal the propagation rules stored in that propagation cookie.

In an embodiment, the rules module 18 is alternatively or also configured to maintain a data structure identifying known (that is, previously determined) propagation cookies and related information—for example, as a database (herein, “ID Database”). The data structure can be updated as new propagation cookies are determined and as the related information is changed. The related information includes, for each user, propagation rules (which may be default or customised).

FIG. 7B shows a method for determining a response by the propagation server 16, according to an embodiment. The method of FIG. 7B assumes that there is already a propagation cookie associated with the particular client device 11 (or more particularly, a web browser of the client device 11)—that is, the web browser has previously visited any one of the web servers 12 irrespective of group 20 or a propagation cookie is newly generated prior to implementing FIG. 7B. The propagation cookies effectively represents a user (or, a particular client device 11 or web browser on a particular client device 11) and can be considered, therefore, an identifier. Therefore, for the purpose of exposition, the content of a particular propagation cookie records a UserID.

In an embodiment, the method of FIG. 7B is performed as part of step 508 of FIG. 5B. In this case, the propagation server 16 is configured to differentiate the information that is stored in the propagation cookie to that which is stored in the domain cookie(s).

At step 700, the rules module 18 receives the information recoded in the propagation cookie (here assumed to be the UserID), and at step 701, receives information identifying the domain of the web server 12 being accessed by the client device 11 (this information can be provided simultaneously).

The rules module 18 then determines the particular propagation rules associated with the user (or, more specifically, the propagation cookie) at step 702. For example, depending on the embodiment, the rules module 18 can obtain the propagation rules from the actual propagation cookie.

In another embodiment, the compares the UserID to the records of the ID database to check is the UserID has previously been stored in the ID database. As with other embodiments, the UserID may be stored in a derived format within the actual propagation cookie, for example, through use of an encryption algorithm. Relevantly, the UserID is derivable from the propagation cookie.

If the rule module 18 cannot determine particular propagation rules (e.g. depending on embodiment, not stored in the propagation cookie or does not exist within ID database), the method proceeds to step 703, where the rules module 18 determines and selects a default ruleset to apply at subsequent step 706. There may be a single default ruleset or there may be a plurality of default rulesets, the rules module 18 being configured to determine one of said default rulesets as appropriate (for example, based on the relevant domain, information about the client device 11, or other factors).

Additionally, at step 704, the rules module 18 stores the selected ruleset as the propagation rules associated with the propagation cookie. For example, in the relevant embodiment, the propagation rules can be set as content of the propagation cookie by setting or updating the propagation cookie on the client device 11. For an embodiment where an ID database is utilised, the rules module 18 stores the selected ruleset within its ID database reference to the propagation cookie information along with a user-specific ruleset which can be simply the same as the selected default ruleset. The user, however, may be provided an option during the method of FIG. 7B, for example by a website redirect or a “pop-up”, to customise the default ruleset before it is recorded as the user-specific ruleset.

On the other hand, if the UserID does exist within the propagation cookie or the ID database (as applicable), the method proceeds to step 705. The rules module 18 selects the particular propagation rules associated with UserId (more particularly, the propagation cookie). The method then proceeds to step 706.

At step 706, the rules module 18 applies the selected ruleset to determine a value for the domain cookie (DomainID) for communication to the relevant domain server 13 (e.g. as used by step 508 of FIG. 5B). Relevantly, the DomainID stored in the domain cookie can be different to the UserID. It should also be understood that, in an embodiment, the rules module 18 can determine to not set a DomainID if the ruleset results in this determination—that is, no domain cookie is generated as a result of the embodiment.

In an implementation, the rulesets are configured to identify domain(s) for which cookie propagation is allowed and domain(s) for which cookie propagation is not allowed. For example, the particular propagation rules may define certain domain(s) for which the user has agreed to allow cookie propagation and/or certain domain(s) for which the user has not agreed to allow cookie propagation.

In the case of user-specific rulesets, a user of a client device 11 for which a propagation cookie has been generated can, in an embodiment, access a dashboard (or other interface) associated with the particular propagation cookie in order to set specific domains as not allowed or allowed. Similarly, the user may be enabled to allow or disallow categories of domains (e.g. all sales domains, all news domains, etc.). The dashboard can be provided as a web site associated with the propagation server 16 (either directly hosted on the propagation server 16 or via a separate web server (not shown)).

Referring back to the groups 20 shown in FIG. 7A, in an embodiment, the rules module 18 is further configured to determine the domain cookie based on the particular domain being accessed by the client device 11. For example, the first group 20 a can be associated with a first-group domain cookie and the second group 20 b with a second-group domain cookie—the particular domain cookie generated therefore depends on the particular group 20. In this example, the domain cookie is set with the value of the first-group domain cookie if the client device 11 is communicating with web server 12 a or 12 b and with the value of the second-group domain cookie if the client device 11 is communicating with web server 12 c or 12 d.

This embodiment may be advantageous where the propagation server 16 and domain servers 13 are provided as part of a service by a service provider for a number of different entities (and therefore, groups 20). Accordingly, cookies are propagated, in effect, only amongst domains of a particular group 20—thus, one entity is not provided with the cookie information associated with another entity. This embodiment may also be advantageous when combined with user control (e.g. via a dashboard) of the user-specific ruleset, as the user is given control over a number of different groups 20 of related domains. For example, if a user selects a category of website to disallow propagation, this selection applies across many different entities. For example, if a user disallows propagation amongst “news websites”, this could apply to the news websites of entity A and the news websites of entity B.

It is also expected that certain implementations will enable a user to agree to have a common domain cookie over two or more groups 20, although it is likely that such cross-group propagation will generally be disallowed by default.

The method of FIG. 7B may be suitable to be performed as part of step 313 or 314 of FIG. 3—that is, when determining the domain cookie to be set on the client device 11. This latter case requires separation between the value of the web page specific data (e.g. ETag) and the domain cookie, where the ETag may take the role of the propagation cookie.

In an embodiment, a previously set domain cookie for a particular domain is modifiable. For example, a user which previously allowed propagation to the particular domain may change to disallow use of the UserID derived information for that domain. Similarly, the user may decide to cancel or delete all reference to the UserID and DomainIDs—the cookies on the client device 11 should be updated to reflect this.

FIG. 7C shows a modification to the method of FIG. 5B—previously described and unchanged steps are as per the previous discussion herein. Modified steps are represented with a “A” suffix. Step 502 always proceeds to step 504—if a domain cookie is identified, then at step 505A, the information indicating the presence of the domain cookie is communicated to the propagation server 16. This can be effected by the propagation server communication instruction causing the client device 11 to communicate the information as part of the request, for example, the information can be passed in a URL or via a suitable network protocol. In an embodiment, the client device 11 communicates a flag indicating the presence of the domain cookie (for example, if the presence of the domain cookie is relevant but the actual content is not relevant for the propagation server 16 to determine to proceed to modified step 506A).

Modified step 506A checks whether the propagation cookie and domain cookie are present on the client device 11. However, the propagation server 16 undertakes a predefined action upon determining that the propagation cookie and the domain cookie are not present. In an implementation, the absence of the propagation cookie is taken to mean the user no longer intends for the information to be available at all—effectively, that a “delete cookie” command should be propagated.

Therefore, at step 507A, the propagation server 16 generates a delete domain cookie instruction which is included within the domain server communication instruction (e.g. as executable code for execution by the web browser of the client device 11) communicated at step 508A, configured to cause the client device 11 to communicate to the original domain server 13 (i.e. in this example, the first domain server 13 a). Alternatively, or in addition, the propagation server 16 can directly effect a redirect (e.g. via Location headers in the response) to the first domain server 163. The domain server communication instruction includes an instruction, understandable by the domain server 13, to delete the domain cookie.

In response, the client device 11 then communicates a request to the first domain server 13 a, at step 510. In response to the request, at step 511, the first domain server 13 a is configured to respond, at step 511A, to the client device 11 with a delete cookie instruction to delete the domain cookie (or, in another implementation, to set it to a null or random value) based on the instruction included within the domain server communication instruction, thereby effectively removing the propagated information.

The response also includes a web server communication instruction (e.g. as executable code) for execution by the web browser of the client device 11 (e.g. in the form of JavaScript code), configured to cause the client device 11 to communicate to the original web server 12 (i.e. in this example, the first web server 12 a). Alternatively, or in addition, the first domain server 13 a can send a redirect instruction (e.g. via Location headers in the response) to the first web server 12 a.

The method then proceeds to web page rendering step 512. At this step, the first web server 12 a communicates with the client device 11 (which may comprise multiple separate instances of communication), however, the generated content is not based on the information which had previously been stored in the first domain cookie.

Regarding FIG. 7C, it should be noted that in a case that both the propagator cookie and the domain cookie are present, the propagation server 16 can either proceed by effectively resetting the domain cookie and/or propagator cookie with their same values, or not sending cookie set commands.

The method can also be modified in relation to the case where the first domain cookie does exist. In this case, the propagation server 16 checks whether the first domain cookie comprises data consistent with a current propagation rules. If the first domain cookie information is inconsistent with the information of the propagation cookie (the comparison involving an application of the propagation rules), the propagation server 16 is configured to determine an update to the first domain cookie. For example, if the user has disallowed propagation for the associated domain, the propagation server 16 can communicate a delete cookie command to the web browser of the client device 11, thereby deleting the domain cookie. If the value for the domain cookie should be changed, this can also be communicated as a new set domain cookie (equivalent to overwrite) command.

The embodiments described with reference to FIGS. 7A-7C may advantageously provide for a balance between privacy, by allowing a user to choose domains to allow cookie propagation, and ecommerce functionality, by enabling content providers to provide tailored content based on consistently identifying a particular user.

It may be desirable to provide means to inform a web browser on a client device 11 that a particular redirect between web resources of different domains is trusted (e.g. the domains of the web servers (and domain servers) and the propagation domain). Similarly, it may be desirable to provide trust in relation to web page specific data (in particular, ETags) that may be associated with a different domain. In each case, the technique involved avoids certain privacy and security issues of third-party cookies, but may still be considered undesirable from a trust perspective.

In an embodiment, a trust signal is defined for which a web browser can be configured to identify. The trust signal should be data that is accessible by the web browser and that can be considered likely, if not certainly, to be controlled and originating from the same entity as controls the particular domain. For example, it can be desirable for the entity that a domain server 12 on a first domain redirecting to, or accessing web page specific data (e.g. ETag) associated with, the propagation domain or another second domain, be enabled to do so, as the entity trust the other domain on account of knowingly implemented a service utilising an embodiment herein described. A suitable trust signal can inform the web browser to allow the interaction with the other domain, even in a case where the web browser would otherwise block such an interaction. For example, certain web browsers have recently stopped providing ETag access across domains.

In the particular embodiment considered, the DNS of the domain of the domain server 12 (i.e. of the entity) is modified—in particular, a record (assumed here to be a TXT record) is entered identifying each trusted domain (for example, as a plaintext list). E.g. in a case of a first domain, second domain, third domain, and propagation domain, the TXT records of the DNS entries for the first domain, second domain, and third domain are modified to refer to each other domain (including the propagation domain).

The DNS TXT record can reliably be assumed to be controlled by the same entity which controls the domain, and can therefore be considered trusted. Additionally, the web browser will likely cache the DNS information during a session in which aa user is accessing the domain on a client device 11. Therefore, the records are available to the web browser (likely in a cache) and can therefore be easily checked.

Therefore, when web browser is instructed to redirect (JavaScript, location header, etc.) or access information of another domain, it compares the other domain with the DNS TXT record to determine if that domain is present. When the web browser stores ETags (cache), for example, it can use the same logic to partition cache based on those domains, so that the same resource is cached across the entire collection and information and cache can be shared. It is also envisaged that this DNS TXT record approach, can be used as “second-party cookie” or “network-cookie” signal, to allow server side cookies to be set for those domains. That is, in effect, a third-party cookie effect (access from other domains) but without the inherent privacy and security issues. This means that if e.g. example.com calls a resource from example01.com, then example01.com can set cookie within a browser that belongs to example01.com despite user being on example.com (i.e. this would normally mean third—party cookie).

Certain advantages of this approach may include one or more of: (1) only a domain owner can control the trust, meaning no JS, browser or anyone else can manipulate this information; (2) even if someone reads TXT records, they mean nothing to them; and (3) if a company adds or removes a domain from their network, changes can be propagated effectively immediately, no updates to websites or any other components are needed.

According to an embodiment, with reference to FIG. 6, there is provided a method for utilising a cookie associated with a content server 14 (a “content cookie”) to determine the value for a domain cookie. Similarly, the method describes using a domain cookie present on the client device 11 for determining a content cookie to communicate to the third-party server 14. This embodiment may advantageously enable a third-party content server 14 to continue to utilise third-party cookies while avoiding setting of such cookies on the client device 11.

In this case, the content server 14 is associated with a different domain to both a web server 12 and its associated domain server 13, and therefore, is barred from directly setting a cookie value on the web browser in response to the web browser accessing the web page of the web server 12 (or at least it is desired for the content server 14 to not set a third-party cookie).

Therefore, the domain server 13 effectively converts cookie values between those present on the client device 11 (domain cookies) and those utilised by the content server 14 (content cookies). The method of FIG. 6 can apply in the case of step 312 of FIG. 3—that is, there is no domain cookie associated with a second web page present. In effect, the domain server 13 converts between the content cookies (being, effectively, third-party cookies) of the content server 14 and first-party cookies set on the client device 11 (the domain cookies).

The content cookie can be associated with different functions. For example, the content cookie can enable tracking amongst different web pages or can provide for improved identify recognition.

According to this embodiment, the web browser communicates a request to the domain server 13 for information provided by the content server 14. The present embodiment thereby utilises the domain server 13 as a proxy for the content server 14. It should be understood that the embodiment described can be utilised using different proxy technologies. It should also be understood that the web content of the content sever 14 can be accessed directly; importantly, however, cookie-related information is passed through the domain server 13 between the client device 11 and the content server 14.

In a particular non-limiting example, the content server 14 can be configured to provide advertising content to the web browser to accompany the content provided by the web server 12. As according to known technologies, the advertising content is provided dynamically and, where available, at least in part based on identifying information associated with the web browser (or, more particularly, the user of the client device 11). In the prior art, this identifying information can be stored within a third-party cookie stored on the web browser—thus, no matter the particular domain being visited while web browsing, targeted advertising can be provided.

At step 600, the web browser communicates to the domain server 13 a request for content from the content server 14 (typically, the request will identify the content server 14 although in some cases the domain server 13 can automatically identify the content server 14). It should be understood that the request can be one that is only expected to return an instruction to set a content cookie associated with the content server 14, although it is generally expected that a response with content for display on the web browser is provided.

The domain server 13 then checks, at step 601, for the presence of a previous set domain cookie, set by the domain server 13 on behalf of the content server 14. Step 601 can comprise implementing the method of FIG. 3 (e.g. including execution of the first code on the web browser)—therefore, if a domain cookie has been set in association with another web page on a different domain, it is propagated to a domain cookie in relation to the present web page's domain and is therefore made available to the domain server 13 in relation to the current web page and is therefore determined as present. Of course, if the domain cookie is already present in relation to the current web page, it will also be determined as present.

If a domain cookie is not set (previously or via propagation), the domain server 13 then communicates a request to the third-party server 14 for the relevant third-party content, at step 602. The request is not accompanied by a content cookie for use by the content server 14— that is, the domain server 13 does not generate a content cookie based on a an existing domain cookie. At step 603, the content server 14 returns (either to the domain server 13 or directly to the web browser of the client device 11) the content. Additionally, the response of the content server 14 includes an instruction to set a content cookie comprising some data. In the advertising content example, the content server 14 can generate a new identifier to accompany content cookie for identifying the client device 11.

At step 604, the domain server 13 generates a domain cookie based on the value of the content cookie set by the content server 14. For example, the domain cookie can be generated according to an encryption algorithm or hashing algorithm applied to the data of the content cookie. The domain cookie can be considered a converted “third-party” cookie, in that the content cookie is associated with a different domain to the domain cookie (and, in addition, the domain of the web server 12). At step 605, the domain server 13 generates and sends an instruction for the web browser of the client device 11 to set the domain cookie (e.g. with an attribute such that the processing server cookie is available to executable code, e.g. by not setting HttpOnly). At step 606 (which typically occurs simultaneously with step 605), the content is communicated from the domain server 13 to the client device 11.

As a result of step 605, a domain cookie has been set on the client device 11 recording information derived from that set by the content server 14 in the content cookie. However, the domain cookie, as discussed, is a first-party cookie. The domain cookie can be propagated in the future as according to, for example, the method of FIG. 3 and is therefore available when the client device 11 visits other related web pages, associated with different domains.

Referring back to step 601, if a domain cookie is set, the domain server 13 then communicates a request to the content server 14 for the relevant content provided by said server 14, at step 610. The request is accompanied by the content of, or derived from, the domain cookie, for use by the content server 14—that is, the domain server 13 communicates a cookie (or said information) based on the domain cookie. At step 611, the content server 14 returns (either to the processing server 13 or directly to the web browser of the client device 11) the content. The content server 14 is not required to generate a new content cookie. Typically, the content is generated at least in part based on the cookie information (derived from the domain cookie) communicated to the content server 14 (e.g. targeted advertising). This content is then communicated to the web browser of the client device 11, for example, via the domain server 13 acting as a proxy, at step 612.

Advantageously, the methods of FIGS. 3 and 6, can operate together to enable an effect similar to that provided by third-party cookies while only setting first-party cookies on the client device 11. That is, a plurality of first-party domain cookies can record the same information derived from the content cookie, each associated with a particular domain. Each domain cookie can then be utilised to generate cookie information for communicating to the content server 14. From the perspective of the content server 14, the same value is received despite the particular web resource being accessed by the web browser of the client device 11, and therefore, the web browser (or the particular user combined with the particular web browser) can be identified—the content server 14 does not require modification in order to provide content and cookies to the client device 11 as the conversion between third-party cookies and first-party cookies is handled by the domain server 13.

In a variation, in relation to the method of FIG. 5B, the propagation server 16 can take the role of the domain server 13 by transcribing between the content cookie from the content server 14 and the domain cookies for each web page domain.

In an embodiment, it is desirable to set an auxiliary cookie for each domain cookie. Each auxiliary cookie can record the same information as its associated the domain cookie, or at least, information derivable from the domain cookie (or from which the domain cookie is derived). In effect, each auxiliary cookie set will comprise representations of the same information, although, typically, the domain cookie is a modified version of the auxiliary cookie, or vice versa. Each auxiliary cookie is set with an attribute barring access by executable code executed on the web browser—that is, for example, the HttpOnly attribute can be set. Such an embodiment can provide an advantage as the domain cookies set due to interactions with the third-party content server 14 can be set without the HttpOnly attribute—thus, the domain cookie is readable by executable code such as JavaScript but the auxiliary cookies are not.

According to this embodiment, each time a domain cookie is set, an auxiliary cookie is also set. However, instead of reading the value of a domain cookie for generating a communication of information to the content server 14, the associated auxiliary cookie is accessed.

In an embodiment, the auxiliary cookie is equal in value to a content cookie, and the domain cookie is an anonymised equivalent of the content cookie. This embodiment can be useful where it is preferred to set a cookie which is not accessible to executable code (e.g. with HttpOnly set) which can comprise non-encrypted information (e.g. in plaintext)—this is, the auxiliary cookie performs a similar function to third-party cookies when set in the prior art. However, the domain cookie is anonymised using an encryption function—therefore, there is lower risk in setting it as accessible to executable code (e.g. without HttpOnly set) as the data contained is not easily readable. The auxiliary cookie can have the effect of being a conversion of the content cookie into a first-party cookie—it appears to have exactly the same content, it is simply set by the domain of the web page rather than a different domain.

Embodiments described herein can be utilised for a variety of implementations. An example previously discussed is for advertising tracking. Another example is user identification for website access purposes. In the prior art, a third-party cookie can be utilised to identify a particular web browser as known for different websites hosted on different domains—in this way, a particular user can avoid identifying themselves each time they visit one of these websites. The embodiments described herein can be utilised to provide the same effect as the third-party cookie while only setting first-party cookies on the client device.

Generally, many situations in which third-party cookies are used in the prior art to provide for websites on different domains to access the same cookie data, certain embodiments may be suitable for providing a similar effect while only setting first-party cookies on the client device 11.

FIGS. 8A and 8B show topologies for implementing an embodiment shown in FIG. 8C and FIG. 8D, in which proxy server 19 is configured to intercept requests directed towards different web servers 12 a, 12 b from the client device 11. The web servers 12 a, 12 b are associated with different domains (e.g. first domain for first web server 12 a and second domain for second webs server 12 b) such that first-party cookies for one domain are not readable by the web server 12 of the other domain, etc. Proxy server 19 can be a logical function of the proxy server 19 or a domain server 13 or can be implemented as a different physical or logical server.

This can be effected in different ways, for example, with reference to FIG. 8A, the proxy server 19 may be associated with the domains of the web servers 12 via suitably configured DNS records, and the proxy server 19 is configured to communicate directly with the web servers 12 (for example, via network 15 or implemented as different logical functions within the same physical hardware or in direct data communication separate to the network 15). The proxy server 19 is configured to identify the appropriate web server 12 for a particular received request based on content of, or associated with, the request.

In another example, as shown in FIG. 8B, the requests are received by the relevant web servers 12, which are then configured to forward the request to the proxy server 19 (for example, via network 15 or implemented as different logical functions within the same physical hardware or in direct data communication separate to the network 15), said requests being modified and returned to the relevant web server 12. Similarly, responses by the web servers 12 are first forwarded to the proxy server 19, which can modify the responses and return to the web server 12, which then communicates the modified responses to the client device 11.

In either example, the proxy server 19 is configured to modify, in certain cases, communications from the client device 11 intended for the relevant web server 12 and, in certain cases, communications from the web servers 12 intended for the client device 11.

Relevantly, the web servers 12 are configured to communicate set cookie commands for setting third-party cookies. The embodiments of FIGS. 8A-8C are configured to modify said commands such as to cause setting of first-party cookies while retaining the information intended for the third-party cookies.

At step 800, the client device 11 communicates a request for content (e.g. via a web page request), which is received by the proxy server 19, at step 801. The request is associated with the first domain (e.g. www.example.com). The request typically will specify a particular web page for which content is desired—it should be noted that a default web page can be selected (e.g. http://www.example.com/index.html). Relevantly, the content which is requested is, at least in part, stored and/or generated by the first web server 12 a. At step 802, the proxy server 19 identifies the intended web server 12 for the request (for this example, assumed to be the first web server 12 a).

Optionally, at step 803, the proxy server 19 generates a modified request based on the received request. The modified request comprises the information of the received request or information derived from said request such as to enable the web server 12 to provide the requested content. Said information can include some or all information of a header of said request. In an embodiment, step 803 comprises copying header and body information of the request when generating the modified request. The modified request may include information such that, when a response is received from the web server 12, it is enabled to identify the original client device 11.

At step 804, the proxy server 19 then communicates the modified request to the first web server 12; that is, the web server 12 a identified at step 802. Relevantly, the modified request identifies the proxy server 19 for receiving a response to the modified request, the response generated by, and received from, the first web server 12 a. That is, from the perspective of the first web server 12 a, the modified request originates from the proxy server 19.

At step 805, the proxy server 19 receives a response generated by the first web server 12 a. The response, for the purposes of exemplifying the method, comprises one or more “set cookie” commands, which are instructions to the web browser of the user device 11 to set a cookie.

The proxy server 19 is configured to analyse the received response in order to determine, at step 806, if one or more set cookie commands are present associated with a domain different to the first domain—any such domains are termed “third-party domains”. If one or more said commands are present, the method proceeds to step 807. Otherwise, the method proceeds to step 808.

In the event that one or more set cookie commands are present, the proxy server 19 is configured to replace reference to the, or each, third-party domain with a new reference to the first domain, at step 807. The proxy server 19 is typically configured to parse the response in order to identify and replace references to third-party domains with the domain of the first web server 12 a, thereby creating a first-party cookie. The content of the first-party cookie can be the same as the third-party cookie.

The response, as processed, is then communicated to the web browser of the client device, at step 808.

FIG. 8D relates to an embodiment which may be optionally implemented with that of FIG. 8C. Steps 800-804 are equivalent to those of FIG. 8C.

As with FIG. 8C, at step 805, the proxy server 19 receives a response generated by the first web server 12 a. The response, for the purposes of exemplifying the present method, comprises executable code (e.g. JavaScript) comprising instructions for the web browser of the client device 11 to undertake one or more instances of communication with one or more content servers 14 (one is assumed here)—herein, content server communication instruction(s). The response also typically comprises content intended for rendering by the receiving web browser and/or executable code for execution by the web browser (e.g. JavaScript).

The proxy server 19 is configured to analyse the received response in order to identify, at step 816, the one or more instances of third-party server communication instruction(s) (e.g. by parsing the response)—that is, instructions to contact another web server 12 such as second web server 12 b.

At step 817, the proxy server 19 is configured to replace reference to the particular web resource of the, or each, third-party server communication instruction with a reference to a dummy web resource, in which the domain of the first web server 12 a is utilised such that the proxy server 19 receives communications directed towards the dummy web resources. The response, as processed, is then communicated to the web browser of the client device, at step 809.

In an embodiment, the proxy server 19 maintains, in a memory, a mapping database in which a mapping record is maintained between generated dummy web resources and the original web resource (i.e. the target of the associated content server communication instruction).

FIG. 8E (which includes steps of FIG. 8D) describes a process whereby the client device 11, upon receiving the executable code of FIG. 8D, communicates with the proxy server 19 via the dummy web resource(s), at step 820. The proxy server 19 compares the dummy web resource(s) to its mapping database to identify the actual third-party web resource (e.g. at the second web server 12 b), at step 821. At step 822, the proxy server 19 determines if there are any cookie on the client device 11 associated with the dummy web resource (and therefore recorded as a first-party cookie of the first domain). Any such cookies are communicated to the third-party web resource (e.g. second web server 12 b) along with a request for content as according to the mapped resource. Assuming a response is received, the content thereof is passed to the client device 11 and, if necessary, the steps of FIGS. 8C and 8D are repeated on this returned content.

In this way, the proxy server 19 can advantageously hide the third-party web resource from the client device 11, while still enabling content to be delivered from the third-party web resource to the client device 11.

Further modifications can be made without departing from the spirit and scope of the specification. 

1. A method for recording information within first-party cookies on a web browser, including propagating recorded information from a second cookie associated with a second domain to a first cookie associated with a first domain, wherein the first cookie and the second cookie are each first-party cookies, such that a first web resource of the first domain and a second web resource of the second domain each have access to the recorded information via its associated first-party cookie.
 2. A method as claimed in claim 1, wherein the recorded information is propagated to the first cookie during a current communication instance between the web browser and the first web resource of the first domain.
 3. A method as claimed in claim 1 or claim 2, wherein the recorded information is propagated to the first cookie in dependence on a determination of the absence of the first cookie.
 4. A method as claimed in any one of claims 1 to 3, wherein the recorded information is propagated via an intermediary, the intermediary being propagation information accessible to the web browser during the current communication instance.
 5. A method as claimed in claim 4, comprising instructing the web browser, during the current communication instance, to communicate to a propagation server associated with a propagation domain different to the first domain, and receiving from the propagation server the propagation information such that the web browser is enabled to record as a first cookie the recorded information.
 6. A method as claimed in claim 5, wherein the web browser initiates the current communication instance via a communication to a first web server requesting content for display, the first web server associated with a first domain server wherein both said servers are associated with the first domain, and wherein the instruction to the propagation server is received from the first domain server.
 7. A method as claimed in claim 6, wherein the first web server provides the content for display to the web browser in dependence on the recorded information after propagation of the recorded information from the second cookie to the first cookie.
 8. A method as claimed in claim 6 or claim 7, wherein, as part of the instruction, the web browser provides information stored in a propagation cookie to the propagation server, and wherein the propagation information is based on the information stored in a propagation cookie.
 9. A method as claimed in claim 8, wherein the information stored in a propagation cookie and the propagation information is the same or wherein the propagation information is an encoded representation of the information stored in a propagation cookie.
 10. A method as claimed in claim 8, wherein the propagation information is generated according to propagation rules available to the propagation server, wherein the propagation rules are applied to the information stored in a propagation cookie.
 11. A method as claimed in claim 10, wherein the propagation rules are stored within the propagation cookie and provided to the propagation server as part of the instruction.
 12. A method as claimed in any one of claims 6 to 11, wherein the propagation information is provided to the web browser in association with an instruction received from the propagation server, such that the web browser is cause to communicate with the first domain server and provides the propagation information with the instruction.
 13. A method as claimed in claim 12, wherein the web browser receives an instruction from the first domain server, in response to providing the propagation information to the first domain server, to set the first cookie comprising the recorded information.
 14. A method as claimed in claim 4, wherein the intermediary is stored as web page specific data, and comprising: instructing the web browser to communicate with a first domain server, the web browser providing the web page specific data to the first domain server with the instruction; and receiving from the first domain server an instruction to set the first cookie with the recorded information, wherein the recorded information is equal to or derived from the web page specific data, wherein the instruction is received from a first web server in response to a request for content for display made by the web browser, wherein the first web server is associated with the first domain server, and wherein both said servers are associated with the first domain.
 15. A method as claimed in claim 14, wherein the web page specific data is set during a previous communication instance with the second domain server of the second domain.
 16. A method as claimed in claim 14 or claim 15, wherein the web page specific data is not accessible to executable code when run on the web browser and is accessible to a first domain server when set by a communication with the second domain, and preferably is only accessible by an external server.
 17. A method as claimed in claim 15 or claim 16, wherein the web page specific data is stored in an ETag associated with a web page provided to the web browser before the instruction is sent to the web browser.
 18. A method as claimed in any one of claims 1 to 17, wherein the first domain and second domain are determined to be related domains for which propagation is allowed before allowing propagation for the recorded information from the second cookie to the first cookie.
 19. A method as claimed in any one of claims 1 to 18, wherein the web browser does not allow access to third-party cookies.
 20. A domain server configured for communication with web browsers for facilitating propagation of recorded information between first-party cookies associated with different domains, the domain server configured to: receive a communication from a web browser due to an instruction provided to the web browser from a first web server associated with the first domain to communicate with the domain server; and determine whether a first cookie is present with the communication, the first cookie associated with the first domain, and wherein, in response to determining that there is not a first cookie present, the domain server is configured to: obtain from the web browser propagation information, the propagation information derived from recorded information of a second cookie associated with a second domain, wherein the recorded information is derivable from the propagation information; determine the recorded information from the propagation information; and instruct the web browser to record in a first cookie the recorded information.
 21. A domain server as claimed in claim 20, further configured to instruct the web browser to communicate with the first web server to enable generation of content for the web browser utilising the recoded first cookie.
 22. A domain server as claimed in claim 20 or claim 21, further configured to, when obtaining the intermediary information: instruct the web browser to communicate with a propagation server associated with a propagation domain different to the first domain, wherein the propagation information is provided to the web browser from the propagation server in response to the instruction; and receive the propagation information from the web browser after the web browser is instructed to communicate again with the domain server.
 23. A domain server as claimed in claim 22, wherein the propagation information is generated according to propagation rules available to the propagation server, wherein the propagation rules are applied to the information stored in a propagation cookie.
 24. A domain server as claimed in claim 23, wherein the propagation rules are stored within a propagation cookie stored in the web browser.
 25. A domain server as claimed in claim 20 or claim 21, wherein the intermediary is stored as web page specific data, and wherein the domain server is further configured to: identify the web page specific data from the communication from the web browser; and communicate an instruction to set the first cookie with the recorded information, wherein the recorded information is equal to or derived from the web page specific data.
 26. A domain server as claimed in claim 25, wherein the web page specific data is set during a previous communication instance with a second domain server of a second domain.
 27. A domain server as claimed in claim 25 or claim 26, wherein the web page specific data is not accessible to executable code when run on the web browser and is accessible to the first domain server when set by a communication with the second domain, and preferably is only accessible by an external server.
 28. A domain server as claimed in claim 26 or claim 27, wherein the web page specific data is stored in an ETag associated with a web page provided to the web browser before the instruction is communicated.
 29. A domain server as claimed in any one of claims 20 to 28, wherein the recorded information is only propagated from the second cookie to the first cookie when the second domain is identified as being related to the first domain.
 30. A domain server as claimed in any one of claims 20 to 29, wherein the web browser in communication with the domain server does not allow access to third-party cookies.
 31. A network system for facilitating propagation of recorded information between first-party cookies associated with different domains on a web browser in communication with the network system, the system comprising: one or more domain servers, wherein each domain server is configured to: receive a communication from a web browser due to an instruction provided to the web browser from a web server associated with the domain; determine whether a first cookie is present with the communication, the first cookie associated with the domain; in response to determining that there is not a first cookie present, obtain from the web browser propagation information, the propagation information derived from recorded information of a second cookie associated with second domain, the second domain associated with another of the domain servers, wherein the recorded information is derivable from the propagation information; determine the recorded information from the propagation information; and instruct the web browser to record in a first cookie the recorded information.
 32. A network system as claimed in claim 31, further comprising a propagation server associated with a propagation domain different to the first domain, and wherein each domain server is further configured to, when obtaining the intermediary information: instruct the web browser to communicate with the propagation server associated with a propagation domain different to the first domain; and receive the propagation information from the web browser after the web browser is instructed to communicate again with the domain server by the propagation server, and wherein the propagation server is configured to: determine the propagation information based on information provided from the web browser with the instruction.
 33. A network system as claimed in claim 32, wherein the information comprises, if present, that stored in a propagation cookie readable by the propagation server.
 34. A network system as claimed in claim 33, wherein the propagation server is configured to generate the propagation information according to propagation rules available to the propagation server, wherein the propagation rules are applied to the information stored in a propagation cookie.
 35. A network system as claimed in claim 34, wherein the propagation rules are stored within a propagation cookie stored in the web browser and are therefore received by the propagation server via the communication from the web browser.
 36. A network system as claimed in any one of claims 33 to 35, wherein in a case where a propagation cookie is not present, the propagation server is configured to determine a value for a propagation cookie and to communicate an instruction to the web browser to set the value as a propagation cookie, and wherein the propagation information are generated in accordance with the newly determined value.
 37. A network system as claimed in claim 31, wherein each domain server is further configured to: identify web page specific data from the communication from the web browser; and communicate an instruction to set the first cookie with the recorded information to the web browser, wherein the recorded information is equal to or derived from the web page specific data.
 38. A network system as claimed in claim 37, wherein the web page specific data is set during a previous communication instance with the second domain server.
 39. A network system as claimed in any one of claims 31 to 38, wherein the recorded information is only propagated from the second cookie to the first cookie when the second domain is identified as being related to the first domain.
 40. A network system as claimed in any one of claims 31 to 39, further comprising a web server for each domain server, wherein the web server is configured to instruct a web browser to communicate with its associated domain server, and wherein each web server shares a domain with its associated domain server.
 41. A network system as claimed in any one of claims 31 to 40, wherein a web browser in communication with the system is assumed to or does not allow access to third-party cookies. 